Chlorogenic acid protects MSCs against oxidative stress by altering FOXO family genes and activating intrinsic pathway

Lavandula angustifolia mill. (Lamiaceae) ethanol extract and its main constituents as promising agents for the treatment of metabolic disorders: chemical profile, in vitro biological studies, and molecular docking

Lavandula angustifolia Mill. (lavender) is one of the most used medicinal plants. Herein, we chemically characterised and investigated the antioxidant properties and the capability to inhibit key enzymes for the treatment of type 2 diabetes (TD2) and obesity such as pancreatic lipase, α-glucosidase, and α-amylase of the ethanolic extract of two lavender samples (La1 and La2) from southern Italy. Both extracts significantly inhibited α-glucosidase, while La1 inhibited α-amylase and lipase more effectively than La2. To investigate whether these properties could be due to a direct interaction of the main constituents of the extracts with the targeted enzymes, molecular docking studies have been performed. As a result, the selected compounds were able to interact with the key residues of the binding site of the three proteins, thus supporting biological data. Current findings indicate the new potential of lavender ethanolic extract for the development of novel agents for T2D and obesity.

Enhancing mesenchymal stem cell survival and homing capability to improve cell engraftment efficacy for liver diseases

Although mesenchymal stem cell (MSC) transplantation provides an alternative strategy for end-stage liver disease (ESLD), further widespread application of MSC therapy is limited owing to low cell engraftment efficiency. Improving cell engraftment efficiency plays a critical role in enhancing MSC therapy for liver diseases. In this review, we summarize the current status and challenges of MSC transplantation for ESLD. We also outline the complicated cell-homing process and highlight how low cell engraftment efficiency is closely related to huge differences in extracellular conditions involved in MSC homing journeys ranging from constant, controlled conditions in vitro to variable and challenging conditions in vivo. Improving cell survival and homing capabilities enhances MSC engraftment efficacy. Therefore, we summarize the current strategies, including hypoxic priming, drug pretreatment, gene modification, and cytokine pretreatment, as well as splenectomy and local irradiation, used to improve MSC survival and homing capability, and enhance cell engraftment and therapeutic efficiency of MSC therapy. We hope that this review will provide new insights into enhancing the efficiency of MSC engraftment in liver diseases.

Effects of dietary supplementation with chlorogenic acid on growth performance, antioxidant capacity, and hepatic inflammation in broiler chickens subjected to diquat-induced oxidative stress

This study was conducted to investigate the protective effects of chlorogenic acid (CGA) on broilers subjected to (DQ)-induced oxidative stress. In experiment 1, one hundred and ninety-two male one-day-old Ross 308 broiler chicks were distributed into 4 groups and fed a basal diet supplemented with 0, 250, 500, or 1,000 mg/kg CGA for 21 d. In experiment 2, an equivalent number of male one-day-old chicks were allocated to 4 treatments for a 21-d trial: 1) Control group, normal birds fed a basal diet; 2) DQ group, DQ-challenged birds fed a basal diet; and 3) and 4) CGA-treated groups: DQ-challenged birds fed a basal diet supplemented with 500 or 1,000 mg/kg CGA. The intraperitoneal DQ challenge was performed at 20 d. In experiment 1, CGA administration linearly increased 21-d body weight, and weight gain and feed intake during 1 to 21 d (P < 0.05). CGA linearly and/or quadratically increased total antioxidant capacity, catalase, superoxide dismutase, and glutathione peroxidase activities, elevated glutathione level, and reduced malondialdehyde accumulation in serum, liver, and/or jejunum (P < 0.05). In experiment 2, compared with the control group, DQ challenge reduced body weight ratio (P < 0.05), which was reversed by CGA administration (P < 0.05). DQ challenge increased serum total protein level, aspartate aminotransferase activity, and total bilirubin concentration (P < 0.05), which were normalized when supplementing 500 mg/kg and/or 1,000 mg/kg CGA (P < 0.05). DQ administration elevated hepatic interleukin-1β, tumor necrosis factor-α, and interleukin-6 levels (P < 0.05), and the values of interleukin-1β were normalized to control values when supplementing CGA (P < 0.05). DQ injection decreased serum superoxide dismutase activity, hepatic catalase activity, and serum and hepatic glutathione level, but increased malondialdehyde concentration in serum and liver (P < 0.05), and the values of these parameters (except hepatic catalase activity) were reversed by 500 and/or 1,000 mg/kg CGA. The results suggested that CGA could improve growth performance, alleviate oxidative stress, and ameliorate hepatic inflammation in DQ-challenged broilers.

Zuogui pills maintain the stemness of oogonial stem cells and alleviate cyclophosphamide-induced ovarian aging through Notch signaling pathway

BACKGROUND

Zuogui pills (ZGP), a classical prescription of traditional Chinese medicine, have been widely used in the treatment of ovarian aging. Previous studies have demonstrated its efficacy on protecting ovarian aging, and the mechanisms were mostly relevant to inhibiting the apoptosis of follicles and activating the primordial follicles. However, whether ZGP could stimulate the oogonial stem cells (OSCs) to refresh the follicle pool remains poorly understood.

PURPOSE

To investigate the effects of ZGP on the stemness of OSCs in cyclophosphamide (Cy)-induced ovarian aging.

STUDY DESIGN AND METHODS

Female Sprague-Dawley (SD) rats were randomly divided into 8 groups: control group, model group, ZGP groups (low / high dose groups), estradiol valerate (EV) groups (low / high dose groups), DAPT group and DAPT+ZGP-L group. After modeling with Cy, the ZGP groups and EV groups were treated with ZGP and EV for 8 weeks respectively. Meanwhile, the DAPT groups were treated with DAPT twice a week. Additionally, OSCs were also isolated after modeling, and then treated with drug serum containing ZGP or EV. Ovarian volume and the ratio of weight of total ovaries to the body weight were measured. The serum hormones were measured by ELISA. Quantities and location of OSCs in ovaries were detected by flow cytometry and immunofluorescence. Cell viability was measured by CCK8. And OSCs were identified by immunofluorescence. Biomarkers of germ cells, stem cells and associated to differentiation and meiosis were detected by qPCR and western blot. Proteins in Notch signaling pathway were detected by western blot and immunofluorescence.

RESULTS

After treating with ZGP, ovarian volume and the ratio of weight of total ovaries to the body weight increased. ZGP could increase serum AMH and E2 level and decrease serum FSH level. Quantities and cell viability of OSCs increased after ZGP treatment in vivo and in vitro. In addition, treatment with ZGP could increase not only the expression of MVH, Oct4 and DAZL, but also the expression of ZP1 and ZP2. Furthermore, ZGP could up-regulate the expression of Notch intracellular domain (NICD), HES1 and HES5. After blocking the Notch signaling pathway, ZGP could increase not only the expression of NICD, HES1 and HES5, but also the expression of MVH, Oct4, DAZL, ZP1 and ZP3.

CONCLUSION

In conclusion, the mechanism of ZGP on treating ovarian aging may be relevant to maintain the stemness of OSCs by up-regulating Notch signaling pathway, which added the mechanism of ZGP on the perspective of OSCs at first time.

Current State of Knowledge on the Antioxidant Effects and Mechanisms of Action of Polyphenolic Compounds

Quality-of-life improvements have resulted in increasing attention being paid to research on antiaging and antioxidation. Polyphenols are natural antioxidants with excellent biological activities, such as antioxidation and scavenging of free radicals and antiviral activity. Abundant availability and low toxicity of polyphenols have attracted the attention of researchers. In this paper, the antioxidant activities of flavonoids, phenolic acids, stilbenes and lignan polyphenols are analyzed, the corresponding antioxidant mechanisms are investigated, and the antioxidant effects of polyphenols are systematically reviewed. Thus, an effective reference based on the recent literature is compiled for the study of the antioxidant mechanisms of polyphenols that provides a significant theoretical basis for the development of products that are components of polyphenols.

New Insights into the Mechanisms of Polyphenol from Plum Fruit Inducing Apoptosis in Human Lung Cancer A549 Cells Via PI3K/AKT/FOXO1 Pathway

Recent studies have been found that polyphenols from plums fruits can inhibit the proliferation of multiple cancer cells, while the molecular mechanism was unclear. This study aimed to investigate the molecular mechanism underlying the pro-apoptotic effect of purified plum polyphenols (PPP) on human lung cancer A549 cells. Quercitrin (quercetin-3-O-glucoside, 814.19 ± 40.71 mg/g) was identified as the primary polyphenol in PPP via ultra high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UHPLC-QqQ-MS/MS). PPP showed a strong capacity for inhibiting the proliferation of the A549 cells by inducing apoptosis, which was reflected by an increase in the Bax/Bcl-2 ratio. Additionally, the inhibitory rate of PPP on the A549 cells were higher than that of vitamin C when the treatment dose exceeded 160 μg/mL. Transcriptome analysis suggested that PPP-induced apoptosis was closely associated with regulating the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/forkhead box protein O 1 (FOXO1) pathway in the A549 cells. Subsequently, as an activator of AKT, SC79 was applied to confirm that the inhibition of AKT phosphorylation play an important role in the PPP-induced apoptosis of the A549 cells. These results illustrated the potential of PPP as a dietary compound for the prevention of cancer or for use during chemotherapy.

Chlorogenic acid co-administration abates tamoxifen-mediated reproductive toxicities in male rats: An experimental approach

Reports over the years have demonstrated toxic side effect-including reproductive toxicity- of tamoxifen (TAM), a drug of choice in the management of primary breast cancer. Chlorogenic acid (CGA), a dietary polyphenol, reportedly elicits beneficial pharmacological effects. However, the impact of CGA on TAM-associated reproductive toxicity is absent in the literature. We, therefore, experimented on CGA's effect and TAM-mediated reproductive toxicity in rats. Cohorts of rats were treated with TAM (50 mg/kg) or co-treated with CGA (25 or 50 mg/kg) for 14 consecutive days. The result showed that treatment of CGA significantly increases testosterone, LH, and FSH levels compared to the TAM group. However, prolactin level was markedly decreased after pretreatment of CGA in TAM-treated rats. CGA abated TAM-induced decreases acid phosphatase, alkaline phosphatase, and antioxidant enzymes in the testis. CGA alleviated TAM-facilitated surges of reactive oxygen and nitrogen species, myeloperoxidase, nitric oxide, interleukin-1β, and tumor necrosis factor-alpha in rats epididymis and testes. Additionally, CGA increased anti-inflammatory cytokine -interleukin-10-, suppressed caspase-3 activity, and reduced pathological lesions in the examined organs of rats co-treated with CGA and TAM. CGA phytoprotective effect improved reproductive function occasioned by TAM-mediated toxicities in rats, by abating oxido-inflammatory damages and downregulating apoptotic responses. PRACTICAL APPLICATIONS: CGA protects against the damaging oxido-inflammatory responses incumbent on TAM metabolism. As an antioxidant abundant in plant-derived foods, CGA reportedly protects against inflammatory damage, hypertension, and neurodegenerative diseases. We present evidence that CGA ameliorates TAM-induced reproductive dysfunction by suppressing oxidative and inflammation stress downregulate apoptosis and improve reproductive function biomarker in rats.

Chlorogenic acid ameliorates memory loss and hippocampal cell death after transient global ischemia

Chlorogenic acid (CGA) is known to have antioxidant potentials, yet the effect of CGA on brain ischemia has not been sufficiently understood. Brain ischemia such as transient global ischemia disrupts many areas of the brain of rats, including the hippocampus. Male Wistar rats were randomly assigned into five groups, that is, sham-operated (SO), bilateral common carotid occlusion (BCCO), and BCCO+ 15, 30, and 60 mg/kg bw CGA groups (CGA15, CGA30, and CGA60, respectively). Brain ischemia was induced in Wistar rats with BCCO for 20 min followed by intraperitoneal injection of CGA. The rats were examined for the spatial memory in a Morris water maze test on the 3rd day and were euthanized on the 10th day after BCCO. The total number of pyramidal cells was estimated, and the mRNA expressions of Bcl2, Bax, caspase-3, SOD2, SOD1, GPx, ET-1, eNOS, CD31, and VEGF-A were measured. The BCCO group spent less time and distance in the target quadrant than any other group in the spatial memory retention test. The CA1 pyramidal cell numbers in the BCCO and CGA15 groups were lower than in the CGA30 and CGA60 groups. The mRNA expressions of Bcl2, SOD2, and CD31 in the BCCO group were lower than in the CGA15, CGA30, and CGA60 groups. The ET-1 expression was higher in the BCCO and CGA15 groups than in the SO, CGA30, and CGA60 groups. CGA improves the spatial memory and prevents the CA1 pyramidal cell death after BCCO by increasing Bcl2, SOD2, and CD31 expressions and decreasing ET-1 expression.

Regulation of the levels of health promoting compounds: lupeol, mangiferin and phenolic acids in the pulp and peel of mango fruit: a review

There is a demand for feasible methodologies that can increase/maintain the levels of health-promoting phytochemicals in horticultural produce, due to strong evidence that these compounds can reduce risk of chronic diseases. Mango (Mangifera indica L.), ranks fifth among the most cultivated fruit crops in the world, is naturally rich in phytochemicals such as lupeol, mangiferin and phenolic acids (e.g. gallic acid, chlorogenic acid and vanillic acid). Yet, there is still much scope for up-regulating the levels of these compounds in mango fruit through manipulation of different preharvest and postharvest practices that affect their biosynthesis and degradation. The process of ripening, harvest maturity, physical and chemical elicitor treatments such as low temperature stress, methyl jasmonate (MeJA), salicylic acid (SA) and nitric oxide (NO) and the availability of enzyme cofactors (Mg²⁺ , Mn²⁺ and Fe²⁺ ) required in terpenoid biosynthesis were identified as potential determinants of the concentration of health-promoting compounds in mango fruit. The effectiveness of these preharvest and postharvest approaches in regulating the levels of lupeol, mangiferin and phenolic acids in the pulp and peel of mango fruit will be discussed. In general spray application of 0.2% iron(II) sulphate (FeSO₄ ) 30 days before harvest, harvest at sprung stage, storage of mature green fruit at 5 °C for 12 days prior to ripening, fumigation of mature green fruit with 10^-5  mol L^-1 and/or 10^-4  mol L^-1 MeJA for 24 h or 20 and/or 40 µL L^-1 NO for 2 h upregulate the levels of lupeol, mangiferin and phenolic acids in pulp and peel of ripe mango fruit. © 2019 Society of Chemical Industry.

Addition of chlorogenic acid and caffeine during the processing of cooled boar semen

ABSTRACT A study was conducted to evaluate the effect of chlorogenic acid (ChA) added pre-cooling and its combination with caffeine added during warming on cooled-stored boar semen parameters. Ten ejaculates were diluted in commercial extender with or without 4.5mg/ml ChA and stored at 15°C. After 0, 24 and 72 hours of storage, aliquots of these doses were taken and incubated at 37°C in the presence or absence of 8.0mM caffeine. Semen quality was evaluated after 10 and 120 minutes of incubation. The ChA increased (P <0.01) the sperm motility, viability, acrosomal integrity and the percentage of spermatozoa with high mitochondrial activity (PMHA), however, decreased (P <0.01) the malondialdehyde (MDA) concentration. Caffeine increased (P<0.05) the sperm motility, viability, PMHA and the MDA concentration and reduced (P <0.05) the acrosome integrity. When associated (ChA+caffeine), there was an increase (P <0.05) in sperm motility and viability, PMHA and acrosome integrity. The addition of ChA to the dilution medium improves the quality of the swine inseminating doses. The addition of caffeine during re-warming is only recommended when the semen is stored for prolonged periods (72h), and the inseminating dose should be used immediately after its addition.

Consumption of Chlorogenic Acids through Coffee and Health Implications

Chlorogenic acids (CGA) are the main antioxidant compounds in the Western diet, due to their high concentrations in coffee associated with the high consumption of the beverage. Until about 10 years ago, like many other phenolic compounds, CGA were thought to be poorly absorbed in the human digestive system. Along the years, large amounts of information on the absorption and metabolism of these compounds have been unveiled, and today, it is known that, on average, about one third of the consumed CGA from coffee is absorbed in the human gastrointestinal tract, although large inter-individual variation exists. Considering results from in vitro animal and human studies, it is possible to conclude that the antioxidant and anti-inflammatory effects of coffee CGA are responsible for, at least to a certain extent, the association between coffee consumption and lower incidence of various degenerative and non-degenerative diseases, in addition to higher longevity.

Supplementing Maturation Medium With Insulin Growth Factor I and Vitrification-Warming Solutions With Reduced Glutathione Enhances Survival Rates and Development Ability of in vitro Matured Vitrified-Warmed Pig Oocytes

The present study sought to determine whether in vitro maturation (IVM) of pig oocytes in a medium supplemented with insulin growth factor-I (IGF-I) and subsequent vitrification with or without reduced glutathione (GSH) affect their quality and developmental competence, and the expression of genes involved in antioxidant, apoptotic and stress responses. In Experiment 1, cumulus-oocyte complexes were matured in the absence or presence of IGF-I (100 ng·mL⁻¹) and then vitrified-warmed with or without 2 mM of GSH. Maturation rate was evaluated before vitrification, and oocyte viability, DNA fragmentation and relative transcript abundances of BCL-2-associated X protein (BAX), BCL2-like1 (BCL2L1), heat shock protein 70 (HSPA1A), glutathione peroxidase 1 (GPX1) and superoxide dismutase 1 (SOD1) genes were assessed in fresh and vitrified-warmed oocytes. In Experiment 2, fresh and vitrified-warmed oocytes were in vitro fertilized and their developmental competence determined. Whereas the addition of IGF-I to maturation medium had no effect on oocyte maturation, it caused an increase in the survival rate of vitrified-warmed oocytes. This effect was accompanied by a concomitant augment in the relative transcript abundance of HSPA1A and a decrease of BAX. Furthermore, the addition of GSH to vitrification-warming media increased survival rates at post-warming. Likewise, the action of GSH was concomitant with an increase in the relative abundance of GPX1 and a decrease of BAX transcript. Blastocyst rates of vitrified-warmed oocytes did not differ from their fresh counterparts when IGF-I and GSH were combined. In conclusion, supplementing maturation medium with 100 ng·mL⁻¹ IGF-I and vitrification-warming solutions with 2 mM GSH improves the quality and cryotolerance of IVM pig oocytes, through a mechanism that involves BAX, GPX1 and HSPA1A expression.

New Challenge: Mitochondrial Epigenetics?

Epigenetics can be explored at different levels and can be divided into two major areas: epigenetics of nuclear-encoded DNA and epigenetics of mitochondrial-encoded DNA. In epigenetics of nuclear-encoded DNA, the main roles are played by DNA methylation, changes in histone structure and several types of non-coding RNAs. Mitochondrial epigenetics seems to be similar in the aspect of DNA methylation and to some extent in the role of non-coding RNAs but differs significantly in changes in components coiling DNA. Nuclear DNA is coiled around histones, but mitochondrial DNA, together with associated proteins, is located in mitochondrial pseudocompartments called nucleoids. It has been shown that mitochondrial epigenetic mechanisms influence cell fate, transcription regulation, cell division, cell cycle, physiological homeostasis, bioenergetics and even pathologies, but not all of these mechanisms have been explored in stem cells. The main issue is that most of these mechanisms have only recently been discovered in mitochondria, while improvements in methodology, especially next-generation sequencing, have enabled in-depth studies. Because studies exploring mitochondria from other aspects show that mitochondria are crucial for the normal behavior of stem cells, it is suggested that precise mitochondrial epigenetics in stem cells should be studied more intensively.

Potential Non-neoplastic Applications for Polyphenols in Stem Cell Utilization

While polyphenols may have important effects on pluripotential stem cells that make them noteworthy as potential antineoplastic agents, their action on stem cells may portend other health benefits, such as treatments for cardiovascular and neurocognitive disorders. Resveratrol, the beststudied polyphenol, has been found to enable stem cells to differentiate into cardiomyocytes, neurons, osteocytes, and pancreatic beta cells, as well as facilitating augmentation of stem cell populations and protecting them from toxic injury. Curcumin protects mesenchymal stem cells from toxicity, and prevents them from facilitating chondrocytic hypertrophy. Quercetin enabled osteocytic and pancreatic beta cell differentiation, and protected neuronal stem cells from injury. Epigallocatechin gallate prevented damage to osteocyte precursors and averted differentiation into undesirable adipocytes. Genistein facilitated osteogenesis while preventing adipogenesis. Several other polyphenols, daidzein, caffeic and chlorogenic acid, kaempferol, and piceatannol, protect stems cells from reactive oxygen species and foster stem cells differentiation away from adipocytic and toward osteocytic lineages. Further research should better elucidate the pharmacokinetic profiles of each polyphenol, explore novel delivery systems, and expand investigation beyond rodent models to additional species.

Role of Chlorogenic Acids in Controlling Oxidative and Inflammatory Stress Conditions

Chlorogenic acids (CGAs) are esters formed between caffeic and quinic acids, and represent an abundant group of plant polyphenols present in the human diet. CGAs have different subgroups that include caffeoylquinic, p-coumaroylquinic, and feruloyquinic acids. Results of epidemiological studies suggest that the consumption of beverages such as coffee, tea, wine, different herbal infusions, and also some fruit juices are linked to reduced risks of developing different chronic diseases. These beverages contain CGAs present in different concentrations and isomeric mixtures. The underlying mechanism(s) for specific health benefits attributed to CGAs involves mitigating oxidative stress, and hence the related adverse effects associated with an unbalanced intracellular redox state. There is also evidence to show that CGAs exhibit anti-inflammatory activities by modulating a number of important metabolic pathways. This review will focus on three specific aspects of the relevance of CGAs in coffee beverages; namely: (1) the relative composition of different CGA isomers present in coffee beverages; (2) analysis of in vitro and in vivo evidence that CGAs and individual isomers can mitigate oxidative and inflammatory stresses; and (3) description of the molecular mechanisms that have a key role in the cell signaling activity that underlines important functions.

Antioxidant property of coffee components: assessment of methods that define mechanisms of action

Coffee is a rich source of dietary antioxidants, and this property, coupled with the fact that coffee is one of the world's most popular beverages, has led to the understanding that coffee is a major contributor to dietary antioxidant intake. Brewed coffee is a complex food matrix with numerous phytochemical components that have antioxidant activity capable of scavenging free radicals, donating hydrogen and electrons, providing reducing activity and also acting as metal ion pro-oxidant chelators. More recent studies have shown that coffee components can trigger tissue antioxidant gene expression and protect against gastrointestinal oxidative stress. This paper will describe different in vitro, cell-free and cell-based assays that both characterize and compare the antioxidant capacity and mechanism of action of coffee and its bioactive constituents. Moreover, evidence of cellular antioxidant activity and correlated specific genomic events induced by coffee components, which are relevant to antioxidant function in both animal and human studies, will be discussed.

The Polyphenol Chlorogenic Acid Attenuates UVB-mediated Oxidative Stress in Human HaCaT Keratinocytes

We investigated the protective effects of chlorogenic acid (CGA), a polyphenol compound, on oxidative damage induced by UVB exposure on human HaCaT cells. In a cell-free system, CGA scavenged 1,1-diphenyl-2-picrylhydrazyl radicals, superoxide anions, hydroxyl radicals, and intracellular reactive oxygen species (ROS) generated by hydrogen peroxide and ultraviolet B (UVB). Furthermore, CGA absorbed electromagnetic radiation in the UVB range (280–320 nm). UVB exposure resulted in damage to cellular DNA, as demonstrated in a comet assay; pre-treatment of cells with CGA prior to UVB irradiation prevented DNA damage and increased cell viability. Furthermore, CGA pre-treatment prevented or ameliorated apoptosis-related changes in UVB-exposed cells, including the formation of apoptotic bodies, disruption of mitochondrial membrane potential, and alterations in the levels of the apoptosis-related proteins Bcl-2, Bax, and caspase-3. Our findings suggest that CGA protects cells from oxidative stress induced by UVB radiation.

SIRT1 inhibits TNF-α-induced apoptosis of vascular adventitial fibroblasts partly through the deacetylation of FoxO1

Sirtuin 1 (SIRT1), a NAD(+)-dependent class III histone deacetylase, participates in regulating cellular apoptosis, senescence and metabolism by deacetylating histones and multiple transcription factors. In this study, we aimed to determine the effect of SIRT1 on the apoptosis of vascular adventitial fibroblasts (VAFs) and related signaling pathways. SIRT1 was found in the nucleus of VAFs and translocated into the cytoplasm in response to tumor necrosis factor-α (TNF-α). Moreover, SIRT1 protein expression was reduced in VAFs stimulated with TNF-α. In addition, TNF-α increased the apoptosis of VAFs. Activation of SIRT1 by resveratrol (RSV) or overexpression of SIRT1 attenuated TNF-α-induced VAF apoptosis by decreasing the percentage of apoptotic cells and cleaved caspase-3 protein expression and increasing the Bcl-2/Bax ratio. In contrast, inhibition of SIRT1 by sirtinol/nicotinamide or knockdown of SIRT1 enhanced apoptosis of VAFs. On the other hand, knockdown of FoxO1 reduced TNF-α-induced VAF apoptosis. SIRT1 interacted with FoxO1 in VAFs by the co-immunoprecipitation assay. Further study showed that RSV or SIRT1 overexpression decreased acetylated-FoxO1 (Ac-FoxO1) protein expression in VAFs stimulated with TNF-α. Knockdown of SIRT1 resulted in an increase in Ac-FoxO1 protein expression. Taken together, these findings indicate that SIRT1 inhibits the apoptosis of VAFs, whereas FoxO1 promotes VAF apoptosis. Furthermore, the inhibitory effect of SIRT1 on VAF apoptosis is partly mediated by the deacetylation of FoxO1.

Cell culture condition-dependent impact of AGE-rich food extracts on kinase activation and cell survival on human fibroblasts

Advanced glycation end products (AGEs) are stable end products of the Maillard reaction. Effects of food extracts are often initially analysed in cellular test systems and it is not clear how different cell culture conditions might influence the results. Therefore, we compared the effects of two models for AGE-rich food, bread crust and coffee extract (CE) on WI-38 human lung fibroblasts under different cell culture conditions (sub-confluent versus confluent cells, with and without serum). WI-38 cells responded to coffee and bread crust extract (BCE) with a rapid phosphorylation of PKB (AKT), p42/44 MAPK (ERK 1/2) and p38 MAPK, strongly depending on culture conditions. BCE resulted in increased cell numbers, whereas CE appeared to be cytotoxic. When cell numbers under all culture conditions and treatments were correlated with kinase phosphorylation, the relation between phospho-p38 MAPK and phospho-AKT represented a good, cell culture condition-independent predictor of cell survival.

Overexpression of human arginine decarboxylase rescues human mesenchymal stem cells against H₂O₂ toxicity through cell survival protein activation

In this study, we explored the potentiality of human arginine decarboxylase (ADC) to enhance the survival of mesenchymal stem cells (MSCs) against unfavorable milieu of host tissues as the low survival of MSCs is the issue in cell transplantation therapy. To address this, human MSCs overexpressing human ADC were treated with H2O2 and the resultant intracellular events were examined. First, we examined whether human ADC is overexpressed in human MSCs. Then, we investigated cell survival or death related events. We found that the overexpression of human ADC increases formazan production and reduces caspase 3 activation and the numbers of FITC, hoechst, or propidium iodide positive cells in human MSCs exposed to H2O2. To elucidate the factors underlying these phenomena, AKT, CREB, and BDNF were examined. We found that the overexpression of human ADC phosphorylates AKT and CREB and increases BDNF level in human MSCs exposed to H2O2. The changes of these proteins are possibly relevant to the elevation of agmatine. Collectively, our data demonstrate that the overexpression of human ADC stimulates pro-survival factors to protect human MSCs against H2O2 toxicity. In conclusion, the present findings support that ADC can enhance the survival of MSCs against hostile environment of host tissues.

High density lipoprotein protects mesenchymal stem cells from oxidative stress-induced apoptosis via activation of the PI3K/Akt pathway and suppression of reactive oxygen species

The therapeutic effect of transplantation of mesenchymal stem cells (MSCs) in myocardial infarction (MI) appears to be limited by poor cell viability in the injured tissue, which is a consequence of oxidative stress and pro-apoptotic factors. High density lipoprotein (HDL) reverses cholesterol transport and has anti-oxidative and anti-apoptotic properties. We, therefore, investigated whether HDL could protect MSCs from oxidative stress-induced apoptosis. MSCs derived from the bone marrow of rats were pre-incubated with or without HDL, and then were exposed to hydrogen peroxide (H₂O₂) in vitro, or were transplanted into experimentally infarcted hearts of rats in vivo. Pre-incubation of MSCs with HDL increased cell viability, reduced apoptotic indices and resulted in parallel decreases in reactive oxygen species (ROS) in comparison with control MSCs. Each of the beneficial effects of HDL on MSCs was attenuated by inhibiting the PI3K/Akt pathway. Preconditioning with HDL resulted in higher MSC survival rates, improved cardiac remodeling and better myocardial function than in the MSC control group. Collectively, these results suggest that HDL may protect against H₂O₂-induced apoptosis in MSCs through activation of a PI3K/Akt pathway, and by suppressing the production of ROS.

Chlorogenic acid inhibits LPS-induced microglial activation and improves survival of dopaminergic neurons

Pro-inflammatory factors released by activated microglia may contribute to the progression of neurodegenerative diseases. As a natural phenolic acid, chlorogenic acid (CGA) has been shown to have anti-inflammatory properties. However, it is unclear whether CGA has the ability to mediate microglial activation. The present study investigated the role of CGA in lipopolysaccharide (LPS)-stimulated microglia. Our data demonstrated that CGA significantly suppressed NO production and TNF-α release in LPS-stimulated primary microglia. In addition, CGA decreased LPS-stimulated phosphorylation and degradation of inhibitory kappa B-alpha (IκBα), and prevented translocation of nuclear factor-kappaB (NF-κB). Furthermore, CGA prevented neurotoxicity caused by microglial activation and ultimately improved survival of dopaminergic (DA) neuron. Finally, in vivo data showed that CGA pretreatment attenuated LPS-induced IL-1β and TNF-α release in substantia nigra (SN). Our results suggested that the pretreatment of CGA significantly inhibits the microglial activation, and CGA may be neuroprotective for pro-inflammatory factor-mediated neurodegenerative disorders.